Question

What is an MCB ? Why it is preferred over a fuse?

Answer 1

Miniature Circuit Breakers (MCB)

The problem with the fuses is that whenever overloading occurs the fuse wire melts and it has to be replaced to complete the circuit. This problem is overcome in miniature circuit breakers (MCBs) which are widely used nowadays. MCBs are switches that turn off automatically when there is an overload or a short circuit. After solving the problem in the circuit, the switch can be turned back on, and then the current flows as usual.

MCB has several advantages over fuse:

1. MCB is more sensitive to current than fuse. It detects any abnormality in the current flow and automatically switches off the electrical circuit.
2. In case of MCB, the faulty zone of electrical circuit can be easily identified. Faulty circuit trips to the off position. On the other hand in case of fuse, the complete fuse wire needs to be checked by opening fuse grip for confirming the faulty zone.
3. With MCB it is very simple to resume to the supply. You just need to push the knob of MCB back to on position. But in case of fuse, the entire fuse wire needs to be replaced.
4. MCB provides a better interfacewith the help of knob than a fuse. In case of fuse the compete handle needs to be taken care out.
5. Handling MCB is electrically saferthan handling a fuse.
6. MCB is reusable and hence hasless maintenance and replacement cost. Whereas a fuse needs to be replaced whenever it goes faulty.